Among well known automotive floor mats is one in which the entire back surface of a mat base member 82 made of a fiber material is covered with a resin sheet 84 and the back surface of the resin sheet 84 seats non-slip projections 86 which project upright as shown in FIG. 13. A floor mat 80 having the non-slip projections 86 hardly gets displaced and will not obstruct safe driving.
During the manufacturing of the floor mat 80 shown in FIG. 13, at the stage of bonding the resin sheet 84 to the back surface of the mat base member 82, a thermoplastic resin extruded into the shape of a sheet and then softened by heat and the mat base member 82 get firmly pressed between a cylindrical mold roller, whose cylindrical surface has concaves having a shape which corresponds to the profile of the non-slip projections 86, and a cylindrical support roller, thereby bonding the mat base member 82 and the resin sheet 84 to each other and simultaneously forming and shaping the non-slip projections 86. Patent Publication JP 2005-313387 A describes such a structure in which paired cylindrical rollers firmly press a mat base member and a resin sheet against each other and accordingly bond them together under pressure and concurrently with the pressure bonding of the resin sheet and the mat base member, non-slip projections are formed and shaped.
However, since the entire back surface of the mat base member 82 is covered with the resin sheet 84 in the floor mat 80 manufactured by the manufacturing method described above as shown in FIG. 13, the resin sheet 84 reflects a sound coming through the surface of the floor mat 80, which is a disadvantage that the acoustic absorption capability of a car flooring material disposed beneath the floor mat 80 deteriorates and noises inside a vehicle are not reduced sufficiently.
A floor mat is known, as shown in FIG. 14, which prevents reflection of noises inside a vehicle in which instead of using a resin sheet, a sound absorbing material 94 is bonded to the back surface of a mat base member 92. This floor mat 90 however, due to the absence of non-slip projections on its back surface, easily gets displaced and could obstruct safe driving.
These problems have given rise to a demand for development of a floor mat whose back surface seats non-slip projections yet whose structure is capable of preventing reflection of in-vehicle noises coming through the surface of the mat. A specific structure of such a floor mat may be to provide spaced apart plural non-slip projections on the back surface of a mat base member. This should permit noises coming through the surface of the mat to be transmitted in the spaces between the non-slip projections, preventing reflection of the noises and obviating displacement of the mat.
However, when one attempts to form plural non-slip projections in a spaced arrangement on the back surface of a mat base member as described above, one can not use a conventional manufacturing technique which requires bonding a resin sheet to the entire back surface of the mat base member. This leads to a demand to newly develop a manufacturing technique for providing spaced plural projections on a surface of a mat base member while attaining an excellent production yield. Such a manufacturing technique can possibly be applied to manufacturing of other products than a floor mat.